Influence of angles and hole pitches on discharge coefficients of expanded holes at inlet and outlet

This paper presented discharge coefficients of the expanded holes at inlet and outlet with plane angles of 20°, 45°, 90°, radial angles of 0°, 30°, 65° and the ratios of pitch to diameter of 2, 3, 4. The momentum flux ratios varied in the range from 1 to 8. The results show that discharge coefficients of radial angle =0° increase significantly when the plane angles increase from 20° to 90°. The effect of plane angle becomes weak with the increasing radial angles. Radial angles have weak influence on the discharge coefficients of plane angle=20° and discharges coefficients of plane angle=45° and plane angle=90° decreases when the radial angles increase from 0° to 65°. Discharge coefficients of plane angle=90° increase when the ratios of hole pitch to the diameter increase from 2 to 4.